BIOAVAILABILITY OF MAGNESIUM CONTAINED IN ROASTED AND GROUND SOYBEAN (KINAKO) AS EVALUATED BY SERUM AND BONE MAGNESIUM CONTENTS, KIDNEY CALCIFICATION, AND MAGNESIUM ABSORPTION

The bioavailability of roasted and ground soybean (kinako) magnesium ( Mg) in Fischer 344 strain male rats with respect to serum Mg level, bo ne Mg contents, kidney calcification, and Mg absorption was evaluated. Four-week-old male rats were divided into four groups of six rats eac h. The four groups were the control (20SC), Mg-deficient diet (1/3 Mg2 0SC), 20SCK diet, and 20SCDK diet. The 20SCK and 20SCDK diets were pre pared to contain amounts of ME equal to that in the 20SC diet with kin ako or defatted kinako as the Mg source, respectively. After a 4-week experimental period, rats were decapitated and blood serum, right femu r, and right kidney were collected, and Mg, calcium (Ca), and phosphor us (P) concentrations in those tissues were determined. The Mg balance was also investigated. The serum Mg concentration in the 1/3 Mg20SC g roup was half the level in the 20SC group, and the serum Ca concentrat ion was higher than in the 20SC group, indicating apparent hypercalcem ia. Serum Mg and Ca concentrations in the 20SCK and 20SCDK groups did not significantly differ from those in the 20SC group. Femur Mg concen tration in the 1/3 Mg20SC group was lower than in the 20SC group. Femu r Mg concentrations in the 20SCK and 20SCDK groups were lower than in the 20SC group, but significantly higher than in the 1/3 Mg20SC group. The kidney Ca concentrations in the 20SCK and 20SCDK groups were sign ificantly higher than those in the 20SC and 1/3 Mg20SC groups, and the re was also kidney calcification. These results indicated that kinako and defatted kinako Mg were used effectively as a serum and femur Mg s ource, but that kinako and defatted kinako carry a risk of kidney calc ification when used as the only Mg source.